docs: def parse_auth_token_from_request(self, auth_header):
          """
          Parses and returns the Hawk Authorization header if it is present and well-formed.
          Raises `falcon.HTTPUnauthoried exception` with proper error message
          """
          if not auth_header:
              raise falcon.HTTPUnauthorized(
                  description='Missing Authorization Header')
  
          try:
              auth_header_prefix, _ = auth_header.split(' ', 1)
          except ValueError:
              raise falcon.HTTPUnauthorized(
                  description='Invalid Authorization Header: Missing Scheme or Parameters')
  
          if auth_header_prefix.lower() != self.auth_header_prefix.lower():
              raise falcon.HTTPUnauthorized(
                  description='Invalid Authorization Header: '
                              'Must start with {0}'.format(self.auth_header_prefix))
  
          return auth_header